Altruism as a memetic weapon

I was getting preached at by my born-again aunt the other day and a thought struck me: One of the compunctions I have against the extermination of religion is the fact that they actually do provide some social services of geniune benefit to society, e.g. helping the homeless, rehabilitating drug addicts and charity work in general. Apart from the obvious benefits to the recipients, this altruism serves the double function of:

1) Making the intellectual murder perpetrated by these religious groups morally defensible; and
2) Strengthening the kinship between members of said religious groups, thus increasing their resistance to external influences.

Oftentimes, I hear religious conservatives, that is, the really, *really* thick ones (see Monique Davis on Wiki) accuse atheists of having no moral guidance and seeking to destroy everything. They'll go on to quote names like Stalin, Mao and Hitler as being the results of atheism. Hitler was Catholic, by the way. And any fool can quote names. Why do they not mention Pope Urban II, who called for the extermination of the Seljuk Turks? Deus vult, indeed. Or Ayatollah Khomeini? Or how about Mother Teresa, responsible for the slow and painful death of millions of impoverished, diseased Indians, withholding adequate medical care and sending all that donated money off to the Vatican so those poor bastards could "die in a state of grace"?

Frankly, I think that's just their childish fear of the unknown talking. A perfectly understandable response from more primitive animals, but religion isn't exactly big on rational thought these days. Atheists are as capable of good and evil as much as the next person and I think I prefer the idea of making a conscious choice to do good without childish lures and threats of Heaven and Hell in a fictitious afterlife, which brings me to the crux of the matter:

What if large numbers of atheists engaged in spontaneous, organised acts of altruism? If society sees that atheists are capable of bringing a clear, tangible benefit to society outside of intellectual spheres (which most of the religious right don't pay attention to anyway) does this not equate to positive publicity and moral high ground for atheism?

The work of 4 Horsemen is all well and good, but I can't help but feel they are, for the most part, preaching to the choir. The kind of people that their works will turn will either be already on the fence or not really religious but just going through the motions out of habit. As for the rest of the atheist community, well, we don't actually need to be reminded that there is no God, do we?

As such, the 4 Horsemen fill the role of providing the intellectual ammunition against God, but atheists have to go above and beyond intellectual achievement. It must be shown to the world at large that atheism is not merely the rejection of faith-based belief, but is the acceptance of rational thought and healthy scepticism with clear and tangible benefit to society outside of the arcane realms of science, which the religiously (and wilfully) ignorant have no interest in anyway.

I think through the practice of public, organised acts of altruism, atheism can fight religious fundamentalism with it's own memetic weapons, and maybe, seeing as we actually have Reason on our side, disseminate a more persuasive message. Thoughts?